I got asked how the scalar product can be used to find the length of a vector? Could someone please explain
Do you mean vector product, also called the dot product?
V°V = |V|^2.
Or do you mean the triple scalar product:
|A°BxC|= volume of the parallelepiped with three sides defined by A,B,C.
If it is the triple scalar product you will need more information to obtain a vectors length - but the dot product provides it immediately.
To my knowledge, the vector product and the dot product are never given the same meaning. The vector product yields a vector quantity; the dot product yields a scalar quantity.